Do you have a dog in the yard? We have abundant skunks, foxes, bobcats, coyotes, raccoons, etc. here and I don't ever recall a chicken being eaten in the daytime.
Our daytime losses were probably raptors. We have a lot.
It's true that we haven't tried free range since we got a dog. I'm pretty sure our current dog would just eat the chickens herself though. She loses her shit over any kind of bird.